In situ fabricated ZIF-8-cellulose nanofibers filter by bottom-up assembly approach for high-efficiency formaldehyde adsorption

Formaldehyde as a common indoor volatile organic compound (VOC) poses serious health risks to humans. Therefore, developing efficient formaldehyde adsorbents is essential for improving indoor air quality. Recently, zeolitic imidazolate framework (ZIF)-based adsorbents have attracted significant attention due to their high efficiency in formaldehyde removal. In this work, cellulose nanofiber (CNF) was used as biomass templates to in situ grow ZIF-8, forming a ZIF-8@CNF filter with enhanced adsorption capacity. The physical–chemical properties of ZIF-8@CNF were investigated using SEM, XRD, FTIR and XPS. The results demonstrate that the successful self-assembly of ZIF-8 crystals onto CNF results in a ZIF-8@CNF filter with a high specific surface area and abundant pore structures. Meanwhile, the ZIF-8@CNF filter demonstrated remarkable formaldehyde adsorption capacity, and achieved 88.32% removal of formaldehyde within 6 h. Additionally, the filter maintains stable structural integrity while retaining over 70% of the formaldehyde adsorption capacity after undergoing five adsorption–desorption cycles, demonstrating outstanding reusability. Furthermore, the adsorption of formaldehyde by the ZIF-8@CNF filter relies on its internal layered porous structure and noncovalent interactions with formaldehyde molecules. Therefore, the as-prepared ZIF-8@CNF filter offers an effective solution for indoor formaldehyde removal.